Gun charger



J. E. CHAPMAN GUN CHARGER Filed Dec. 17, 1941 Spt. 11,1945.

4 Illllllllllllllllllllllllllilllll! *Y l m /M Y v I Jam Echa/0172;? E BY ATTRNQ/ Patented Sept. ll, 1,945

f UNITED STATES PATENT vori-lcs GUN CHARGER James E. Chapman, Los Angeles, Calif., assignor to North American Aviation, Inc.,'Inglewood, Calif., a, corporation of Delaware 4application December 17, 1941, Sena1N0. 423,355

Claims. (C1. 89-1) v y l gun, the parts being inthe normal lposition ready The present invention relates generally to machine guns and more particularly to the charging of the gun to feed thereto another shell in the event of failure of the previous shell to're, there being in such an instance no recoil of the charging mechanism to effect gun-actuated feed of a new shell as there is in ordinary continuous In guns of small calibre the charging bolt may be readily drawn back by hand and a Vnew'shell fed into the gun' before release of the bolt so it may move to charging position under the actuation' of its spring which is placed under compression when the bolt is drawn back. However, in guns of larger calibre, such, for instance, as fifty calibre guns now preferred in airplanes, the charging spring is of such strength that it is impractical for the bolt to be drawn back Vby hand.

It is the primary objectof this invention to shift the gun bolt back, or retract the Vsame from charging position'by spring retracting means of a strength substantially greater'than the strength of its charging spring, thus placing the latter under compression during retraction of the bolt, and tothen release the bolt at the end of its retracting movement, for forward or'charging movement under its own charging spring.

Itis afurther object to-normally7 hold the spring retracting means in a compressed condition at all'times and to` automatically release the same, for action within'a predetermined interval or period after failure of the gun to fire, by an V electrical control means which will function to recompress the spring retracting means, after retraction and release of the'gun bolt, so that said means will be restored to'a condition ready foragain operatingto the rdesiredend in the event of a subsequent failure of the gun to fire.`

The invention, "therefore, contemplates an automatic" electrical power and'control for the entire cycle of charging a new shell whenever a shell fails tori-ire. This automatic retraction ofA the gun bolt operates the 'usual means of discharging the previous shell and Afeeding' a new shell intofthefchamber of the gun.4 v

Itis to accomplish the foregoing in a practical effective manner that there is suggested the means to be now described in detail, as to construction and assembly, as well as operation, reference being. made in such description to the accompanying drawing whichforms a part of this specification, andin which,

1 is a top plan view showing the mecha' nism'v ofthe present invention assembled on a longitudinal spring holding tubes for operation.' f

Fig. 2 is a side view thereof.

Fig. 3 is a detail horizontal sectional view on an enlarged scale, lshowing the normally latched portions of the rack, the dog-carrying spring crosshead.

Fig. 4 is a diagram illustrating the electrical control and operating connections.

Fig. v5 is a fragmentary vertical sectional view through portions of the spring holders and the spring actuated crosshead.

Referring now particularly t0 Figs. 1 and 2, there is shown a pair of vertically spaced parallel I0 andy II mounted, as by means of a supporting bracket, including end members I2 and I3 at the forward and rear ends of the tubular holders, at one side of a machine gunIlI so that the gun bolt I5 is opposite the spaceY betweenv the holders and in its forward, or. gun charging position, is intermediate of the ends 'of the tubes.

.The tubularholders I0 and .II have facing longitudinal slots throughA which the laterally Y extending end portions I6 of a crosshead I1 project to form abutmentsfor the rear ends of springs I8 housed by the tubes with their for'- ward ends abutting the'forward closed ends of the tubes. Thus the springs I8 are compressed .by forward movement of the crosshead I1 and,

when the crosshead is free to move rearwardly, the springsexert their combined strength to effect such movement. The combined strength of springs I8, it may be said at this point, is sub-V stantially greater than the strength of the recoil spring of the gun charging mechanism, the

movement the shell previously fired is discharged and a new shell fedinto the vgun forv the next firing operation. When a shell fails to fire there is no recoil and h ence no charging operation,` and in guns of greater' than thirty calibre it is' impractical to pull the gun bolt I5 rearwardly by hand against the tension, which is necessary in such guns, of the recoil spring I9.

According 'to the present invention, the Icrossf head I'I isonormally latched in a position for-v wardly of .the forward'charging position of the again shift'the charging bolt to forward position,I

accomplishing by spring means what ordinarily.

results from recoil in the gun.

The invention controls, byelectrc1m.eans,;the

There is also supported on the bracket in connection with, and extending above, the tubular spring holders I and I I, a motor 35, the housing of which encloses areduction gear for its depending driven shaft 36. This shaft extends vertically, downwardly and carries on its lower end a pinion 31 in mesh with the teeth 38 along the outerfface of the rack bar .21. Also on the shaft 36.there are iixedcams 39'aboverand`below the rack bar 21 which, when rotated by rotation of said shaft, engage at their ends with the upper and lower ends of pin 32. It will be observed that .whenepinion 31 and its shaft 36 are rotated clockwise in Fig to causeinitial rearward movement release of the crosshead after apredetermined f interval following failure of the gun Ato fire, and also provides for the forwardcreturnof the crosshead I1 after release from the gun bolt, to again place its actuating springs I8 under compression and once again-set the parts in anormal latched position ready for effective operation :when the gun fails to fire.

In order to engage the gun bolt I5, the cro-sshead I1 is provided'uponfitsfinnerface-opposing the-gun I4, with a pivoted, vertically swinging dog 20. This dog has an upper engaging nose=2I :and a rearwardly and downwardlyiinclined tail 2,2. A stationary block r22? is positioned :on the supporting bracket.y ofthe spring holdersln and I.I, at approximately the forwardlimitof rmovement of the crosshead I1 and 'when the tail 22 of the dog .2B yrides on this ,block,"its fnose -is.lif.ted, forwardly of the .gun Ibolt ;I5`.in;the forward charging position of tthe latter. Thuswhenthecmsshead is vreleased,'the=,nose2?.l of degli! engages the bolt ,and the latter will tbefmoved rearwardly with the crosshead since 'the rlatterzmoves Iin sa path. coinciding withthe path'of kretractile movementof the bolt, though itis understood .the Vactual yposition of `the crosshead .itself iis :slightly beyond the free end 'of the' bolt.

,At 'the rear end ofrthe tubular holders rIIJ and I-I ,zthe rear end piece I 3 of thefsupporting bracket has ra projecting .fpin '.234/.as seeniin Figure :2, and when the crosshead I1, carryingmhe bolt ..I 5 rearwardly as above, reaches kthe end Yof itsrearward movement, the tail I22 v'of:dog;?.ll frides underpin 2'4 :and .fis 'thus :shifted :downwardly .to with-draw itsfnoseZI fromzinfront of the gun `:bolt I5. Thus the .gun bolt .released 'for forward ymovement under :the effect of `itscompressed recoilspring I9.

VIt will beinoted in Figs. i3 and.5 .that the crosshead I-1 has upper and .lower recesses 2l]a facing the dog L and vthat the latter lhas a spring. .pressed latch ball Ha. Thus'the-dog willbe held ineither its upper or lower positionyuntil shifted by the block -23 orspin'24.

'I'he latch lwhichnormally holds'the cross head I1 in forward-positionis shownfinlig. 3 as of the shape of a bifurcated;bellcrank25, 'pivoted intermediateits ends vat 26pm the upper and lower surfaces of anelongated rack member .21 atthe rear end of the latter, The-'rearwardlyrextending latch arm vv28 of latch member 25 "substantially parallels 'the'rack yIoar321 Vand1has=at lits rear end of rackijbarZLthecams acting against pin 32 in rfitslowermost position, will shift the latch arms 3!) rearwardly and, since the latch member is, in

effect, a bell-crank, will force the latch arm 28 sition of rest. vToward the end of this'movement.

the .rotating cams y39 merely shift the pin 32`in the ,slots 3I vof the. latch Ymember against the tensionpfrspring 33 without tending to shift the'positionof-the latchmember and hence the crosshead Acontinues to followthe rack 'bar in its forward movementzand `remains in latched connec.

tion .therewith .after the rack bar'has Acompleted itsy return movementand motor i35.is1deenergized. During this/movement .thesprings I8 are again placed undercompression and thus all parts fare restored to position Yready vfor a subsequent yoperation.

.The electrical .control of .the motor .35 is in ac- 4 cordance with .the diagram of .Fig.l4wherein the motor is shown fas 'a split .eld reversible type. According to .the diagram, current `isavaila'ble to the controlling :circuits from a1 source of current 40, rwhenever the main switch -4I, or firingkey, is closed for supplying .current 4to the gunI ring solenoidline 41. -A timedelayrelay switch F43 remains .inactive as long vas current is normally utilized inthe firing of the gun. In thebrief `in tervals betweennormal ring of Ythe gun, the gun bolt I5 momentarily closes the switch 48. 'The remainder-of the timethe switch v48'is open. This momentary closing ofthe switch v48 closes 'the following circuit: source Y4I), wire`14, resistance 13, wire 44, switch 48, wire 56, switch 54 and'ts ground. 'During .momentary closing of this switch .4,8 which is at the `'time the gun bolt is in its forward or charging position, the-'resistance 13 does notfheat up sufciently'to closesaid contacts of the relay 43. However, when :the gun fails to fire, thegun bolt 48 'maintains .thelswitch 48 closed, thus permitting the .resistance 13 `to continue to heat up. The Yresistance .13 is sufliciently close to the spaced contactsofthe relay 43, to heat such contacts when the resistance .1 3 becomes heated. When the spaced contacts of the relay 143 become heated to a predetermined point, they contact each other, thus closing the last-described circuit, When saidbontacts engage each other, they complete a circuit from thesource, through Wires 14,46, 45 Yand 515` and? ani electro-magneti 41. r

- When'.electro-'magnet 41 'isi thus'. energizedf'it' draws :armatures -49and 50;V respectively, against Vcontacts and 52, contact 5l vbeing connected'to feed line 53, and contact 52 beinggrounded. A groundedr reversing switch I 54 `isV shown 1inv the starting position, and 'a holding circuit isztlius formed from feed line 53, through contact 5l, armature 49, wire 55,wi'e 46, electro-magnet 41, Wire 45, wire 56 and reversing switch 54 to ground. At the same time current flows from feed line 53 through motor 35 and its field 51, in the direction of arrow 58, wire 59, armature 50, and contact 52 to ground, so that the motor operates in a direction lto shift the rack bar 21 rearwardly and initially release the crosshead for rearward movement to retract 4the gun bolt I5. As soon as the gun bolt starts rearwardly the switch 48 is permitted to open, thus breaking the time delay relay circuit.

The rack bar 21 is thus moved rearwardly to reengage the crosshead until a projection 6U adjacent the forward end of rack bar engages reversing switch 54 and shifts the same from contact with wire 5B to contact with wire 6|. In thus shifting the reversing switch, the holding circuit is broken, armatures 49 and 5U return to their normal positions, and the motor circuit through field 51 is broken. In thereversed position of switch 54, however, current flows from the feed line 53,

through motor 35, and its field 62, in the direc-V tion of arrow 63, wire 6l and switch 54 to ground, thus reversing the motor and causing the return, forward movement of rack bar 21, with the relatched crosshead I1, to normal forward position. As such position is reached, a projection B4 at the rear end of the rack bar engages and shifts the reversing switch 54 back to contact with wire 56 so that the motor stops and the parts are thus restored to the normal forward latched position ready for a fur-ther operation any time the gun fails to fire.

In thus providing for retraction of the charging mechanism of the gun in an entirely automatic manner involving the use of springs for bringing about retraction of the gun bolt, it is plain that the invention imparts to the charging mechanism a movement which very closely approaches its movement under recoil in normal gun operation.

While I have illustrated and described what I now regard as the preferred embodiment of my invention, the construction is, of course, subject to modifications without departing from the spirit and scope of my invention. I, therefore, do not wish to restrict myself to the particular form of construction illustrated and described, but deside to avail myself of all modifications that may fall within the scope of the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. An electrically controlled bolt retracting mechanism for machine guns, lcomprising a frame, a bolt retracting member movably mounted for reciprocation on said frame and adapted to be positioned forwardly of the path of reciprocation of the gun bolt during normal gun operation, said member including means engageable with the bolt, spring means connected between said frame and said member to actuate said member for bolt retracting movement, said spring disposed on said frame to be recompressed by said member during the return of said member to its forward position, means positioned on said frame in the path Cil of reciprocation of said member to disengage said bolt engaging means from the bolt at the end of bolt retracting movement, and electrically controlledl means positioned on said'frame to hold said-member in'fitsforward position, said electrif cally controlled means including means to release said member for bolt retraction and'means to return said member to its forward'position.

2*.` vAn electrically `controlled bolt retracting mechanism forrmachinegu'ns, comprising a frame, al -boltnetracting 'member movably mounted for reciprocation on said frame and adapted to be positioned forwardly of the path of reciprocation of the gun bolt during normal gun operation, said member including means engageable with the bolt, spring means connected between said frame and said member to actuate said member for bolt retracting movement, and having a force exceeding the compressed force of the recoil spring of the gun bolt, said spring disposed on said frame to be recompressed by said member during the return of said member to its forward position, means positioned on said frame in the path of reciprocation of said member to disengage said bolt engaging means from the bolt at the end of bolt retracting movement, and electrically controlled means positioned on said frame to hold said member in its forward position, said electrically controlled means including cam means to release said member for bolt retraction and means to return said member to its forward latch held Position.

3. An electrically controlled bolt retracting mechanism for machine guns, comprising a frame, a bolt retracting member movably mounted for reciprocation on said frame and adapted to be positioned forwardly of the path of reciprocation of the gun bolt during normal gun operation, said member including means engageable with the bolt, spring means of greater strength than the recoil spring of the gun both connected between said frame and said member to actuate said member for bolt retracting movement, means .for normally maintaining said spring under compression, means positioned on said frame to disengage said bolt engaging means from the bolt at the end of bolt retracting movement, and electrically controlled means positioned on said frame to hold said member in its forward position, said electrically controlled means including means to release said member for bolt retraction upon failure of the gun to fire and means to return said member to its forward position.

4. An electrically controlled bolt retracting mechanism for machine guns, comprising a frame, a bolt retracting member oscillatably mounted on said frame a latch for holding a bolt retracting member in non-effective position during normal gun operation, said bolt retracting member including means engageable with the bolt upon release of the latch, spring means connected between said frame and said member to actuate said member for bolt retracting movement, said spring disposed on said frame to be recompressed by said member during the return of said member to its latched position, means on said frame to disengage said bolt engaging means from the bolt at the end of bol-t retracting movement, and electrically controlled means positioned on said frame to hold said bolt retracting member to its latched position, said electrically controlled means including means to actuate the lat-ch to release said member for bolt retraction and means to return said member to its latched position.

5. An electrically controlled and actuated bolt retracting mechanism for machine guns, combetween said frame and said crcsshead. to actnatezv said. crosshead for' bol-t, retracting.. movement, said; spring disposed on said frame-to he recompressed by said crosshead during mnvement. of said crosshead reversely to its bolt. retracting movement,

means positioned on saidframe in the path of re-v 10 ciprocation of said crosshead toV disengage said answersy boltreng'agi-ng means' from the bolt. at the endy 011 bolt retracting movement, and electrically con@ trolled and actuated means positioned onsad frame including a latch to render said crcsshead non-effective, saidv electrically controlled means including a cam constructed and arranged to release said crosshead from said latch for bolt retraction and means to return said crosshead to itsv non-effective,y latched position.

' JAMES =E.` CHAPMAN.. 

